Thiocarbamic acid-s-esters of benzimidazoles



United States Patent M 3,345,377 THIOCARBAMIC ACID-S-ESTERS 0F BENZIMIDAZOLES Karl Goliasch, Schildgen, and Heinrich Pelster and Hans Scheinpflug, Leverkusen, Germany, assignors to Farbenfabriken Bayer Aktiengesellschaft, Leverkusen, Germany, a corporation of Germany No Drawing. Filed Dec. 23, 1964,'Ser. No. 420,813 Claims priority, application Germany, Jan. 25, 1964,

F 41,834 8 .Claims. (Cl. 260309.2)

The present invention relates to new thiocarbamic acid- S-esters which have fungitoxic properties, and to a procin which R stands for hydrogen, alkyl, alkoxy and/or halogen,

A stands for alkylene with 1-10 carbon atoms.

R stands for halogen, alkoxy, haloalkoxy, alkyl-cyclo alkoxy or alkylmercapto, and

It stands for an integer of 1-2,

have strong fungitoxic properties.

It has also been found that thiocarbamic acid-S-esters of the Formula I are obtained, when mercapto-benzimidazoles of the general formula 3,345,377 Patented Oct. 3, 1967 in which R and n have the meaning stated above,

are reacted, in the presence of a base, with isocyanic acid esters of the general formula R -AN= C=O in which A and R have the meaning stated above.

It must be regarded as definitely surprising that the thiocarbamic acid-S-esters obtainable according to the invention have such strong fungicidal properties, since compounds vof similar chemical structure have hitherto not been known to possess a high fungicidal activity.

When the process according to the invention is started from mercapto-benzimidazole and 1-chloro-6-isocyanatohexane, the reaction can be illustrated by the following reaction scheme:

The starting materials are clearly characterised by the above Formulae II and III. In these formulae, R preferably denotes alkyl with 1-6 carbon atoms, alkoxy with 1-4 carbon atoms, chlorine and bromine; A preferably means alkylene with 1-8 carbon atoms, and R chiefly denotes chlorine, bromine, alkoxy with 1-10 carbon atoms, haloalkoxy with 1-10 carbon atoms and containing chlorine and/or bromine, alkylcycloalkoxy with 1-10 carbon atoms, and alkylmercapto with 1-6 carbon atoms.

Examples of Z-mercapto-benzimidazoles which can be used according to the invention as starting materials, are: 2 mercapto benzimidazole, 4 methyl-, 5 methyl-, 6- methyl-, 4,5-dimethyl-, 5-methyl-6-tert.butyl, 5-methoxy-, 5-ethoxy-, 6-ethoxy-, 4-chloro-, 5-chloro-, 6-chloro-, 5,6- dichloro-, 5-bromo-, 4-bromo-5-methyl and 6-bromo-2- mercaptobenzimidazole.

As examples of isocyanic acid esters to be used according to the invention there may be mentioned: I- ch1oro-ethyl-2-, 1-chloro-propyl-3-, 1-chloro-butyl-4-, 1- chloro-hexyl 6-, 1 chlorobutoxy-propyl-, methoxymethyl-, methoxy propyl-, ethoxy-propyl-, i-butoxypropyl-, 2-methyl-cyclohexyloxy-propyl-, i-octyloxy-propyl-, 2-ethyl-hexoxy-propyl-isocyanate.

Suitable diluents are all inert organic solvents, such as chlorinated hydrocarbons, e.g., ethylene chloride, dichloro-benzene or nitrobenzene, but also ketones, such as cyclohexanone, as well as dimethyl formamide, dimethyl sulphoxide and pyridine, or mixtures of these solvents. However, it is also possible to work without asfolvent. Lower aliphatic alcohols, such as methanol and isopropanol may. also be used.

As catalytically active bases, amines are chiefly used, preferably tertiary amines, such as triethylamine and pyridine.

The reaction temperatures can be varied within a fairly wide range. In general, the process is carried out between and 180 C., preferably between and 100 C,

For carrying out the process according to the invention, about 1 mol of isocyanic acid ester is used per mol of Z-mercapto-benzimidazole, but it is also possible to use an excess of isocyanic acid ester. The reaction and the working up are carried out in the usual manner.

The substances according to the invention have a strong fungitoxic effect and are distinguished by a broad spectrum of activity. Due to their low toxicity towards warmblooded animals, they are suitable for combating undesirable fungus growth. Their good compatibility with highor plants enables them to be used as plant protective agents against fungus diseases.

The compounds according to the invention have proved especially satisfactory for controlling rice diseases. They have an excellent protective effect when combating Piricularia oryzae and Cochliobolus miyabeanus in rice.

The compounds according to the invention also have a particularly good activity against a number of other fungi, such as species of Mycosphaerella and Cercospora, and against Botrytis cinerea. They also have a fungitoxic elfect on fungi which attack the plants from the soil, sometimes causing tracheomycoses, such as Phialophora cinerescens and VerticiZliu-m alboatrum.

Since the compounds according to the invention; as leaf fungicides, have mainly a protective elfect, a mixture with curative agents is advantageous. Organic mercury compounds, suc h ;as phenyl-rnercury acetate, and also antibiotics, such as Blasticidin S, are suitable for this purpose. By adding the compounds according to the invention, a substantial reduction of the mercury content can be achieved in the mixed preparation. The disadvantages occurring when organic mercury compounds are used by themselves, such as the high toxicity towards warmblooded animals, can thus be reduced. By combining preparations of protective and of curative effect, as in the mixture mentioned above, an increased effectiveness can be attained.

T e mpqu sa dins 1 th? i v ut nw b t a formed into the usual formulations, such as emulsifiable concentrates, spray powders, pastes, soluble powders, dusts and granulates. These are prepared in known manner; for example by extending the active ingredients with solvents and/orcarriers ifdesired with the use of emulsifiers and/ or, dispersing agents (of. Agricultural Chemicals, March 1960, pages 35 38), Suitable auxiliaries for, this purpose are mainlysolvents, such as aromatics (e.g., xylene, benzene), chlorinated aromatics, (e,g., chl orobenzene's), parafiins (e.g., petroleumfractions), alcohols (e.g.,, methanol, butanol), amines e.g., ethanolamine, dimethyl formamide), and water; carriers, such as natural rock flours (e.g., kaolins, aluminas, talc, chalk) and ground synthetic stone (e.g., highly dispersed silicic acid, silicates); emulsifiers, such as non-ionic and anionic emulsifiers (e.g., polyoxyethylene-fatty acid esters, polyoxy A. ethylene-fatty alcohol thers, alkylsulphonates and arylsulphonates), and dispersing agents, such as lignin, sulphite waste liquors, and methyl cellulose.

The active compounds according to the invention can be present in the formulations in admixture with other known active ingredients.

The formulations generally contain between 0.1 and 95, preferably between 0.5 and 90, percent by weight of active compound.

The compounds to be used or their preparations are applied in the usual manner, for example by spraying, dusting, sprinkling or atomizin'g. The active ingredient can be used in concentrations between 0.2 and 0.005 percent, dependent upon the intended application. In special cases, however, it is also possible to exceed or to remain below this range of concentration.

The following examples are given for the purpose of illustrating the invention.

Example A Piricularia test/liquid preparation of active compound:

Solvent 1 part by weight acetone. Dispersing agent 0.05 part by weight sodium oleate. Other additives 0.2 part by weight gelatin. Water 98.75 parts by weight H O.

The amount of active compound required for the desired concentration of the active compound in the spray liquidis mixed with the stated amount of solvent, and the concentrateobtained is diluted with the stated amount of watercontaining the stated additives. I H

Thirty rice plants which are about 14 days old,a re sprayedwith the spray liquid until dripping wet. The plants remain in a greenhouse at temperatures of 22 to 24 C. and at a relative atmospheric humidity of about 70%. They are then inoculated with an aqueous suspension of 100,000 to 200,000 spores/ml. of Piricularia oryzae and placed in a room at 2426 C. and at a relative atmospheric humidity of Five days after inoculation, the infestation of all the leaves of the treated plants, which were present at the time of inoculations,- are determined as a percentage of the untreated, but also inoculated control plants. 0% means that no infestation occurred, and 100% means that the infestation is exactly the same as that of the control plants.

The active compounds, their concentrations and the results obtained can be seen from the table below (Table 1).

Example B The amount of active compound required for the desired concentration of the active compound in the dusting agent is mixed with the stated amount of solvent, and the concentrate obtained is triturated in a mortar with the stated amount of dust base, until the solvent has evaporated.

Thirty rice plants which are about 14 days old, are dusted with this agent. They are then inoculated with an aqueous suspension of 100,000 to 200,000 spores/ml. of Piricularia! oryzae and placed in a room at 2426 C. and

a relative atmospheric humidity of 100%.

Five days after inoculation, the. infestation of all the leaves of the treated plants, which were present at the time of inoculation, are determined as a percentage of the untreated, but also inoculated control plants. 0% means that no infestation occurred, and 100% means that the infestation is exactly the same as that of the control plants.

3,345,377 5 3 The active compounds, their concentrations and the temperature of about 42 C., and then poured into Petri results obtained can be seen from the following Table dishes of 9 cm. diameter. Control dishes without the (Table 1): active compound are also provided.

TABLE 1 Ph'icularia test/liquid preparation of active compound=l Piricularia test/solid preparation of active compound=s Infestation in percent of infestation of untreated control at a concentration of active Active compound compound of (percent)- C-S-CO-NH-(CHMCI CSCoNH-(0H1)a-OC H NH CSOO-NH(OH );-O--CH(CH2)2 CSC O--NH(C Han-S0211, H

Example C When the nutrient medium has cooled and solidified, Myoelium growth test Nutrient medium: the dISheS are inoculated with the fungi specified 1n the Parts by weight powdered agar-agar 20 table and mclfbated about 21 Parts by weight malt extract Evaluation is carried out after 4-10 days, dependent Parts by weight distilled water 950 upon the rate of growth of the fungi. For evaluation the radial mycelium growth on the treated nutrient media is Ratlo of solvent to nutnent medlum' compared with the growth on the control medium. The Parts by weight actone 20 evaluation of the mycelium growth is made as follows: Parts by weight agar nutrient medium 100 The amount of active compound required for the demycelium gTowth sired concentration of the active compound in the nutrient medium is mixed with the stated amount of the solvent. The concentrate obtained is thoroughly mixed in the 1Very strong inhibition of growth; 2Medium' inhibition of growth; 7 3-S1ight inhibition of growth;

stated ratio with the liquid nutrient medium which has a 4-Gr0wth equal to that of untreated control.

, ether and filtered off With suction. Yield 61.2 g. (98.7%

The active compounds, their concentration and the results obtained can be seen from the following table (Table 2):

8 zene and 050 ml. of dimethyl for narnide at 50 C. for 4 hours. After distilling olT the solvent and squeezing the slightly greasy residue on clay, 26.8 (63.6% of the theo- TABLE 2.-MYCELIUM GROWTH TEST Fungi Cone. of active Active compound com- Piricu- Cochlio- MZ/CO- Cercos- Cercos- Botry- Phia- Vertipound/ Zaria bolus sphaepom pom tis ZOPIZOTG cillium p.p.m. oryzae mz'yaberella percofcinerea cinealbaanus musicola sonata feicola rescem atmm o-s-o-NH-(om @o1 50,0 2 2 3 2 2 1 100 4 4 4 4 4 2 NH O-SCONH(OH2)zOOzH5 500 2 2 1 2 1 100 4 3 4 3 2 G-S-CONH(CH)a-OCH(CH3): 500 1 1 0 0 0 0 1 4 3 2 3 2 1 2 Example 1 retical) remain as yield: M.P. 163C. (from ethanol). N The following compounds are prepared in analogy to the process described above:

Sfi-NH-(CH2)a-Cl N 0 f S(JNH(CH Cl H 330 o 'N- (ti-chlorohexyl) -thiocarbamic acid-S- (2) benzimidazolyl ester 42.0 g. of 1-chl0rohexyl-6-isocyanate, 30.0 g. of 2-rnercapto-benzimidazole and 2 ml. of pyridine are heated at 60 C. for 6 hours, While stirring. The initially thinly liquid, White slurry gradually solidifies. After cooling, the dirty-White residue is stirred With 100 ml. of petrgleur'n of the theoretical); white crystals of M.P. 150-160 C.

Example 2 Exain'ple 3 N (Z-ethyImercarito-ethyl)rthiocarbamlc acid-S- (2) benzimidazolyl ester 1 22.5 g. of 2-rnercapto-benairnidaiole, 20.7 g. of 05% 2-ethylmercaptoethyl isocyanate and l nil. of pyridine are heated in a solvent mixture of ml. of 1,2-dichloroben- N- G-chloro-hexyl) -thi0carban1ic acid S- 2 6-methyl 1 benzimidazolyl ester: M.P, 271 C.

.N- 3-ethoxy-propy1) -thioearbamic acid-S ('2) -[*6'ehl oro]- benzirnidazolyl ester: M.P. 257 C. V

:N- methoxy-methyl) -thiocarbamic acid-S- (2) benzimidazolyl ester M.P. C.

#N- (3-isopropoxypropyl thiocarbaniic item-sl2 -bnz"iin idazolyl ester: M.P. 138 C.

N- 3-ethoxy-pr0py1) -thlocarbamie acid-S- (2') [-methy1] benzimidazolyl ester: M.P. 290 C.

N- (2-chloro-ethy1) -thi0carbam1c acid-S- (2) -benzimid azolyl ester: M.P. 167 C. V

1N-[3-(2-methyl)-cyelohexoxy-propyl thiocarbamie acid-S (2)-benzimidazoly1 ester: M.P. 149-50 C.

N- 2-chloro-ethyl) -thlocarbamic acid-S-[Z- E-ethoxy) benzimidazolyl] ester: M.P. 172 C.

We claim: 1. A compound of the formula 3. A compound of the formula in which B is an alkylene of 1-8 carbon atoms; and R is an alkylmercapto of 1-6 carbon atoms.

4. A compound of the formula in which B is defined as alkylene of 1-8 carbon atoms; and R is chloro.

5. A compound of the formula 6. A compound of the formula 7. A compound of the formula 8. A compound of the formula C-S-CO-NH-(CHah-SCaEh References Cited UNITED STATES PATENTS Searle 260-455 Tilles et a1. 260-455 Tilles et a1. 260-455 Campbell et a1 260455 Jacobi et al. 260-455 Wagner 260309.2 Zellner 260309.2 Miller 167-33 Metivier 260-455 Grewe 167-33 OTHER REFERENCES in which B is an alkylene of 1-8 carbon atoms and R is alkoxy of 1-10 carbon atoms.

Macko Chem. Abst., vol. 53, column 3204 (1959). Mamedov et al.: Izvestia Akad. SSSR. Ot del. Khim. Nauk, 1964, page 700 relied on (April 1964).

WALTER A. MODANCE, Primary Examiner.

S. I. FRIEDMAN, N. TROUSOF, Assistant Examiners. 

1. A COMPOUND OF THE FORMULA 